Today’s Google Doodle celebrates Martin Luther King Jr.’s “I Have a Dream” speech, which he gave on August 28, 1963 during the March on Washington for Jobs and Freedoms at the Lincoln Memorial. The speech is considered a defining moment in the American Civil Rights Movement, and was in response to the civil rights legislation President Kennedy had proposed in June of that year.

The speech had originally been planned as an homage to Abraham Lincoln’s Gettysburg Address, however due to concerns about keeping the demonstration calm, King instead gave the speech that became commonly known as “I Have a Dream”.

The most famous line from the speech, and the one that is most often quoted, expands to “I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin, but by the content of their character. I have a dream today!”

It isn’t very well-known that the speech was actually a combination of several drafts written, and the speech was originally titled “Normalcy, Never Again”. The end of the speech actually wasn’t from his prepared speech at all, but was more of a sermon prompted by someone in the crowd, resulting in a much stronger emphasis on the idea of dreams than originally intended.

While he was speaking, African-American gospel singer Mahalia Jackson called to King from the crowd, saying “Tell them about the dream, Martin!” This resulted in King stopping the speech he had prepared, and ended up preaching, focusing on dreams.

The speech was highly publicized in the press after the event, with most of the comments regarding the eloquence of King’s speech, and the way he touched the crowd with his words. King was named to the Man of the Year by Time magazine for both 1963 in 1964, following the speech. He also became the youngest person ever awarded the Nobel Peace Prize, when he won it in 1964.

Interestingly, despite the speech being so well-known in American history, the full text of the speech wasn’t published until 15 years after King’s death, when the Washington Post published it in August 1983. It has since been added to the United States national recording Registry, and the National Park Service is also commemorated him with a marble pedestal at the location gave a speech at the Lincoln Memorial.

After King gave a speech, he gave his typewritten speech to George Raveling, a basketball player from Villanova who happen to be on the podium with King as the speech ended, as he was a security guard for the event. However in earlier version of the “Normalcy, Never Again” speech is part of the Morehouse College Martin Luther King Jr. Collection at the Robert W. Woodruff Library in Atlanta.